My table of Integrals has the final situation ##int frac dx x^two+a^2 ## like a 'normal' integral also, not simply the situation where ##a=one##. But I do think this becoming a Calculus homework dilemma it is anticipated with the OP to determine how to make it happen. Hints got higher https://gabletoppak.com/the-growing-threat-of-marine-pollution-and-how-gabletop-cartons-offer-a-solution/